problem1 link 暴力枚举即可. problem2 link 一共有24小时,所以最多有24个顾客.设$f[x][y][z]$表示还剩下$x$把刀,现在时间是$y$,以及来过的顾客集合为$z$可以获得的最大值. 那假设第$y$小时来的顾客为$t$,来的概率为$p$,有三种情况: (1)之前它来过,那么$f[x][y][z]=f[x][y+1][z]$ (2)之前没来过,现在也没来,$f[x][y][z]=(1-p)*f[x][y+1][z]$ (3)之前没来过,现在来了.可以选择买给他…
problem1 link 倒着想.每次添加一个右括号再添加一个左括号,直到还原.那么每次的右括号的选择范围为当前左括号后面的右括号减去后面已经使用的右括号. problem2 link 令$h(x)=\sum_{i=1}^{x}g(i)$,那么答案为$h(R)-h(L-1)$.对于$h(x)$: (1)如果$x\leq K$,那么$h(x)=0$ (2)否则对于$[K+1,x]$之间的所有偶数来说,对答案的贡献为$even+h(\frac{x}{2})-h(\frac{K}{2})$,其中$e…
Problem Statement You are given the ints perimeter and area. Your task is to find a triangle with the following properties: The coordinates of each vertex are integers between 0 and 3000, inclusive. The perimeter of the triangle must be exactly…
Problem Statement The Happy Letter game is played as follows: At the beginning, several players enter the field. Each player has a lowercase English letter on their back. The game is played in turns. In each turn, you select two players with dif…
